Drum brake shoe adjuster

Abstract

The invention discloses a brake shoe adjuster. In a preferred embodiment, the invention discloses floating adjusters with a single adjusting rod. One specifically disclosed embodiment shows an hydraulic adjuster with an adjusting rod, forming a plunger or piston, in an hydraulic cylinder, and driven by grease forced into the cylinder by a grease gun through a zerk grease fitting. Another specifically disclosed embodiment shows a mechanical adjuster with a rod, forming a rack, driven by a pinion gear.

What I claim is:  
     
       1. A floating drum brake shoe adjuster comprising: 
       a drum brake back plate having an adjuster access passage,  
       a drum brake shoes mounted to the back plate,  
       an hydraulic cylinder having an outer body and one open end, a closed end, and a bore formed between the open and closed ends of the cylinder, and a grease access passage adjacent to the closed end of the bore, and a ram portion, located on the outer body of the closed end of the cylinder, for engaging a drum brake shoe,  
       a hollow access shaft having a cylinder end and a grease fitting end, wherein the cylinder end is connected to the grease access passage, and a grease fitting is connected to the grease fitting end, and wherein the shaft extends through the adjuster access passage of the back plate,  
       a plunger slidably riding in the bore, wherein the plunger has a piston end and a ram end for engaging a drum brake shoe, and wherein the piston end is tapered to prevent the plunger from blocking the grease access passage, and  
       wherein the cylinder is not fixed to the back plate and can float.  
     
     
       2. A floating drum brake shoe adjuster comprising: 
       a drum brake back plate having an adjuster access passage,  
       a pair of drum brake shoes mounted to the back plate,  
       a floating hydraulic cylinder having an open end and  
       a closed end forming a bore, wherein the bore has an annular groove adjacent the open end for receiving an O-ring, and wherein the closed end has a slotted ram for engaging one of the pair of drum brake shoes,  
       a passage adjacent the closed end of the cylinder affording fluid access to the bore,  
       a fluid valve connected to the passage by a fluid valve passage, wherein the valve allows fluid to be pumped into the bore, and wherein the fluid valve is accessible through the adjuster access passage, and  
       a plunger slidably riding in the bore, wherein the plunger has a piston end and a ram end for engaging a second of a pair of drum brake shoes, and wherein the piston end is tapered.  
     
     
       3. The drum brake shoe adjuster of  claim 2  wherein the fluid valve is a grease fitting. 
     
     
       4. A floating drum brake shoe adjuster comprising: 
       a drum brake back plate,  
       a pair of drum brake shoes mounted to the back plate,  
       a floating hydraulic cylinder having an open end and a closed and forming a bore, wherein the bore has an annular groove adjacent the open end for receiving an O-ring, and wherein the closed end has a slotted ram for engaging one of the pair of drum brake shoes,  
       a passage adjacent the closed end of the cylinder affording grease access to the bore,  
       a grease fitting connected to the passage by a grease shaft, wherein the grease fitting allows grease to be pumped through the shaft and into the bore,  
       an adjuster access passage in the back plate through which the grease shaft extends, wherein the adjuster access passage is of sufficient size to permit the grease shaft clearance to allow the hydraulic cylinder to float between the brake shoes, and  
       a plunger slidably riding in the bore, wherein the plunger has a piston end and a ram end for engaging a second of a pair of drum brake shoes, and wherein the plunger's piston end is tapered to prevent the plunger from blocking the passage.